TECHNICAL FIELD
[0001] The present invention relates to a probe pin, for example, a probe pin to be incorporated
into an IC test socket.
BACKGROUND ART
[0002] Patent Literature 1 discloses one example of conventional probe pins (see Fig. 6
of Patent Literature 1). This probe pin includes an upper contact pin and a lower
contact pin which have the same shape, and a coil spring. The upper contact pin and
the lower contact pin are connected to each other inside the coil spring so as to
be orthogonal to each other. The upper contact pin has a pair of hooks placed in a
groove of the lower contact pin, and the lower contact pin has a pair of hooks placed
in a groove of the upper contact pin.
CITATION LIST
PATENT LITERATURE
SUMMARY OF INVENTION
TECHNICAL PROBLEM
[0004] However, since the foregoing probe pin in an operated position is restored to its
original position only by the spring force of the coil spring. Consequently, when
the coil spring is reduced in size, satisfactory spring force cannot be obtained.
For this reason, the probe pin cannot be restored to the original position and an
operation failure might occur, causing the problem of not being able to reduce the
size of the entire probe pin.
[0005] In view of the foregoing problem, an object of the present invention is to provide
a small-sized probe pin with high reliability.
SOLUTION TO PROBLEM
[0006] A probe pin according to the present invention is characterized by comprising:
a coil spring; and
first and second plungers each provided with a body portion and a sliding piece that
extends from the body portion and has a slide contact surface,
the first and second plungers being respectively inserted from both ends of the coil
spring toward an inside of the coil spring, and the slide contact surfaces being disposed
in a reciprocable manner along an axis center of the coil spring while being in slide
contact with each other, and the coil spring being held between the body portion of
the first plunger and the body portion of the second plunger,
the first and second plungers being close to each other, and a contact area where
the slide contact surface of the first plunger is in contact with the slide contact
surface of the second plunger being tilted with respect to the axis center,
when the coil spring is compressed by external force to apply loads of pressing forces
in directions of the axis center to the first and second plungers, resultant forces
of component forces of the pressing forces in the directions of the axis center, the
component forces being generated between the slide contact surfaces by spring forces
of the first and second plungers, and the spring force of the coil spring acting in
a direction to restore the first and second plungers to original positions of the
first and second plungers before the compression of the coil spring.
ADVANTAGEOUS EFFECTS OF INVENTION
[0007] According to the present invention, the first plunger and the second plunger are
respectively provided with the siding pieces having the slide contact surfaces that
are in slide contact with each other. The first and second plungers are formed such
that the contact area of the slide contact surfaces of the sliding pieces is tilted
with respect to the axis center when the coil spring is compressed by the external
force to apply loads of the pressing forces in the direction of the axis center to
the first and second plungers. For this reason, when the loads of the pressing forces
in the direction of the axis center are applied to the first and second plungers,
the sliding pieces of the first and second plungers are both elastically deformed,
and the component forces of the pressing forces in the direction of the axis center,
the component forces being generated by the spring forces of the elastically deformed
sliding pieces, acts in such the direction to restore the coil spring to the original
position before the compression of the coil spring. This allows the use of the coil
spring with the spring force smaller by the component forces of the spring forces
of the sliding pieces in the direction of the axis center, thereby reducing the size
of the coil spring and reducing the size of the entire probe pin.
[0008] Hereinafter, a position of each of the first and second plungers before the loads
of the pressing forces in the direction of the axis center of the coil spring are
applied by the external force to the first and second plungers to compress the coil
spring will be referred to as an "original position", and a position of each of the
first and second plungers after the loads of the pressing forces in the direction
of the axis center of the coil spring are applied by the external force to the first
and second plungers to compress the coil spring will be referred to as an "operated
position".
[0009] Further, according to an embodiment of the present invention, the coil pin may be
configured as follows. The sliding pieces of the first and second plungers are curved
from the body portions toward free ends of the sliding pieces so as to intersect with
the axis center from directions different from each other.
[0010] According to the present embodiment, the sliding pieces of the first and second plungers
are curved from the body portions toward the free ends of the sliding pieces so as
to intersect with the axis center of the coil spring from the directions different
from each other. Therefore, when the loads of the pressing forces in the direction
of the axis center are applied to the first and second plungers, the sliding pieces
of the first and second plungers are both elastically deformed, and the component
forces of the pressing forces in the direction of the axis center, the component forces
being generated by the spring force of the elastically deformed sliding pieces, acts
in the directions to restore the first and second plungers to the original positions.
This allows the use of the coil spring with the spring force smaller by the component
forces of the spring forces of the sliding pieces in the direction of the axis center,
thereby reducing the size of the coil spring and reducing the size of the entire probe
pin.
[0011] Further, according to an embodiment of the present invention, the probe pin may be
configured as follows. The free end of the sliding piece of the first plunger has
a Y-shaped cross section, and the sliding piece of the second plunger has a cross
section slidable on an inner surface of the free end of the first plunger.
[0012] According to the present embodiment, the sliding piece of the second plunger slides
on the inner surface of the free end, which has the Y-shaped cross section, of the
sliding piece of the first plunger. Therefore, when the loads of the pressing forces
in the direction of the axis center are applied to the first and second plungers,
the sliding piece of the first plunger is elastically deformed by being pressed by
the second plunger, and the component forces of the pressing forces in the direction
of the axis center, the component forces being generated by the spring force of the
elastically deformed sliding piece, act in the directions to restore the first and
second plungers to the original positions. This allows the use of the coil spring
with the spring force smaller by the component forces of the spring forces of the
sliding pieces in the direction of the axis center, thereby reducing the size of the
coil spring and reducing the size of the entire probe pin.
[0013] According to an embodiment of the present invention, the probe pin may be configured
as follows. The first plunger has a first support projection protruding from the body
portion, and a first falling preventive bump protruding from the first plunger at
a position apart from the first support projection by a certain distance. The second
plunger has a second support projection protruding from the body portion, and a second
falling preventive bump protruding from the second plunger at a position apart from
the second support projection by a certain distance. One end of the coil spring is
held between the first support projection and the first falling preventive bump, and
the other end of the coil spring is held between the second support projection and
the second falling preventive bump.
[0014] According to the present embodiment, the two ends of the coil spring are respectively
held between the first and second support projections and the first and second falling
preventive bumps. This prevents wobbling of the coil spring and prevents falling of
the coil spring.
[0015] Further, an electronic device according to the present invention is characterized
by including the probe pin.
[0016] According to the present invention, it is possible to provide a small-sized probe
pin.
BRIEF DESCRIPTION OF DRAWINGS
[0017]
Fig. 1 is a perspective view showing an original position of a probe pin according
to a first embodiment of the present invention.
Fig. 2 is a front view of the probe pin in Fig. 1.
Fig. 3A is a side view of the probe pin in Fig. 1, and Fig. 3B is a sectional view
taken along line III-III in Fig. 3A.
Fig. 4A is a top view showing a state in which the probe pin in Fig. 1 is placed in
a housing, and Fig. 4B is a sectional view taken along line IV-IV in Fig. 4A.
Fig. 5 is a perspective view showing an operated position of the probe pin according
to the first embodiment of the present invention.
Fig. 6 is a front view of the probe pin in Fig. 5.
Fig. 7A is a side view of the probe pin in Fig. 5, and Fig. 7B is a sectional view
taken along line VII-VII in Fig. 7A.
Fig. 8 is a perspective view showing an original position of a probe pin according
to a second embodiment of the present invention.
Fig. 9 is a front view of the probe pin in Fig. 8.
Fig. 10A is a side view of the probe pin in Fig. 8, and Fig. 10B is a sectional view
taken along line X-X in Fig. 10A.
Fig. 11A is a top view showing a state in which the probe pin in Fig. 1 is placed
in a housing, and Fig. 11B is a sectional view taken along line XI-XI in Fig. 11A.
Fig. 12 is a perspective view showing an operated position of the probe pin according
to the second embodiment of the present invention;
Fig. 13 is a front view of the probe pin in Fig. 12.
Fig. 14A is a side view of the probe pin in Fig. 12, and Fig. 14B is a sectional view
taken along line XIV-XIV in Fig. 14A.
DESCRIPTION OF EMBODIMENTS
[0018] Hereinafter, a probe pin according to the present invention will be described in
detail based on embodiments shown in the drawings.
(First Embodiment)
[0019] As shown in Figs. 1 to 3B, a probe pin 1 according to a first embodiment of the present
invention includes a first plunger 10, a second plunger 20, and a coil spring 30.
The first plunger 10 and the second plunger 20 have electrical conductivity and are
formed by electroforming, for example. The coil spring 30 is not shown in Figs. 1
and 2 for convenience of the description.
[0020] As shown Figs. 1 and 2, the first plunger 10 has a body portion 11 and an elastic
sliding piece 12 each having the same width.
[0021] The body portion 11 has a substantially rectangular shape in plan view. The body
portion 11 has, at one longitudinal end 11a thereof, a tip portion 14 having a triangular
shape in plan view. The elastic sliding piece 12 is disposed on the other longitudinal
end 11b of the body portion 11 so as to extend from the other end 11b along an axis
center C of the coil spring 30. The other longitudinal end 11b of the body portion
11 is also provided with support projections 15, 15 protruding in a short direction.
[0022] The elastic sliding piece 12 is made up of a thick portion 12a and a thin portion
12b, and one end of the thick portion 12a is connected to the body portion 11. Further,
both side faces of the thick portion 12a are provided with falling preventive bumps
16, 16. A certain clearance is defined between the support projections 15, 15 and
the falling preventive bumps 16, 16 of the body portion 11. Further, the thin portion
12b is connected to one portion obtained by dividing the thick portion 12a into two
portions in a thickness direction. The thin portion 12b of the elastic sliding piece
12 is curved from a bottom surface 12d to a top surface 12e so as to intersect with
the axis center C of the coil spring 30 shown in Fig. 2, and a free end 12c is formed
at the tip of the thin portion 12b. The free end 12c is curved from the top surface
12e to the bottom surface 12d of the thin portion 12b.
[0023] As shown in Figs. 1 and 2, the second plunger 20 has the same configuration and shape
as those of the first plunger 10. That is, the second plunger 20 has a body portion
21 and an elastic sliding piece 22 each having the same width. The body portion 21
has a tip portion 24 at one longitudinal end 21a thereof. The elastic sliding piece
22 is disposed on the other longitudinal end 21b of the body portion 21 so as to extend
from the other end 21b in the longitudinal direction. The other longitudinal end 21b
of the body portion 21 is also provided with support projections 25, 25 protruding
in a short direction.
[0024] The elastic sliding piece 22 is made up of a thick portion 22a and a thin portion
22b, and one end of the thick portion 22a is connected to the body portion 21. Further,
both side faces of the thick portion 22a are provided with falling preventive bumps
2 6, 26. A certain clearance is defined between the support projections 25, 25 and
the falling preventive bumps 26, 26 of the body portion 21. Further, the thin portion
22b is connected to one portion obtained by dividing the thick portion 22a into two
portions in a thickness direction. The thin portion 22b of the elastic sliding piece
22 is curved from a bottom surface 22d to a top surface 22e so as to intersect with
the axis center C of the coil spring 30, and a free end 22c is formed at the tip of
the thin portion 22b. The free end 22c is curved from the top surface 12e to the bottom
surface 22d of the thin portion 22b.
[0025] In the first plunger 10 and the second plunger 20, slide contact surfaces 17, 27
for ensuring the electric conduction while coming into slide contact with each other
are provided on the top surfaces 12e, 22e of the thin portions 12b, 22b of the elastic
sliding pieces 12, 22. The slide contact surfaces 17, 27 are surfaces that come into
contact with each other when the first plunger 10 and the second plunger 20 slide.
In the probe pin 1 according to the first embodiment, the slide contact surfaces 17,
27 cover from the free ends 12c, 22c of the thin portions 12b, 22b to the thick portions
12a, 22a.
[0026] Surface treatment such as plating or coating can be performed on the slide contact
surfaces 17, 27 or all or part of the first plunger 10 and the second plunger 20 in
accordance with the design.
[0027] The coil spring 30 is made of carbon steel or stainless steel, for example. As shown
in Figs. 3A and 3B, the coil spring 30 has an inner diameter slightly larger than
a width W1 of each of the thick portions 12a, 22a of the first and second plungers
10, 20. Further, the coil spring 30 has an outer diameter slightly smaller than a
total width W2 of the body portions 11, 21 and the support projections 15, 25 of the
first and second plungers 10, 20.
[0028] In a state in which the first plunger 10 and the second plunger 20 are both placed
in a housing 40 (shown in Figs. 4A and 4B), a spring length of the coil spring 30
is previously adjusted such that force in a compressing direction is applied (i.e.,
such that the spring force of the coil spring 30 acts in directions to separate the
first plunger 10 and the second plunger 20 from each other).
[0029] The first plunger 10 and the second plunger 20 are slidably combined as follows.
[0030] First, the first plunger 10 and the second plunger 20 are respectively inserted from
both ends of the coil spring 30 toward the inside of the coil spring 30. The first
plunger 10 and the second plunger 20 are disposed on the axis center C such that the
free ends 12c, 22c of the elastic sliding pieces 12, 22 comes face to face.
[0031] When the first plunger 10 and the second plunger 20 are inserted from both the sides
of the coil spring 30 toward the inside of the coil spring 30, a first end 30a of
the coil spring 30 is engaged with and held by the support projections 15, 15 and
the falling preventive bumps 16, 16 of the first plunger 10, and a second end 30b
of the coil spring 30 is engaged with and held by the support projections 25, 25 and
the falling preventive bumps 26, 26 of the second plunger 20.
[0032] At this time, the free end 12c of the elastic sliding piece 12 of the first plunger
10 and the free end 22c of the elastic sliding piece 22 of the second plunger 20 are
not in contact with each other.
[0033] As shown in Figs. 4A and 4B, next, the first plunger 10 and the second plunger 20
are brought close to each other and then are further pressed to the inside of the
coil spring 30 until the free end 12c of the elastic sliding piece 12 of the first
plunger 10 and the free end 22c of the elastic sliding piece 22 of the second plunger
20 come into press contact with each other. The first plunger 10 and the second plunger
20 are placed into the housing 40 in the state of being pressed inside the coil spring
30.
[0034] At this time, the support projection 15 of the first plunger 10 and the support projection
25 of the second plunger 20 are defined in shape so as to come into contact with the
inner wall of the housing 40 in the state in which the first plunger 10 and the second
plunger 20 are pressed inside the coil spring 30. That is, the displacement of the
first and second plungers 10, 20 in a direction orthogonal to the stretching and compressing
directions of the coil spring 30 in the housing 40 is regulated by the support projections
15, 25. This enables efficient displacement of the first and second plungers 10, 20
in the direction of the axis center C of the coil spring 30.
[0035] Further, since the elastic sliding piece 12 of the first plunger 10 and the elastic
sliding piece 22 of the second plunger 20 are curved so as to intersect with the axis
center C of the coil spring 30 from different directions, the slide contact surface
17 of the first plunger 10 and the slide contact surface 27 of the second plunger
20 are in contact with each other at the free ends 12c, 22c in the state of being
tilted with respect to the axis center C.
[0036] Further, in the first plunger 10 and second plunger 20 placed in the housing 40,
the free end 12c of the elastic sliding piece 12 of the first plunger 10 and the free
end 22c of the elastic sliding piece 22 of the second plunger 20 are constantly in
press contact with each other and are constantly brought into conduction with each
other. Accordingly, the first plunger 10 and the second plunger 20 can be brought
into conduction with each other via the free ends 12c, 22c being a press contact area,
and can obtain stable electric contact.
[0037] Further, the movement of the coil spring 30 in the stretching direction is restricted
by the support projections 15, 25, and the movement of the coil spring 30 in the compressing
direction is restricted by the falling preventive bumps 16, 26. This can prevent wobbling
of the coil spring 30 and can also prevent falling of the coil spring 30, thus preventing
dismantling of the probe pin 1.
[0038] Further, providing the support projections 15, 25 allows efficient transmission of
the spring force of the coil spring 30 to the first and second plungers 60, 70.
[0039] Note that the support projections 15, 25 of the first plunger 10 and the second plunger
20 may have any shape and size which can limit the movement of the coil spring 30
in the stretching direction and can regulate the movement of the first plunger 10
and the second plunger 20 in the direction orthogonal to the stretching and compressing
directions of the coil spring 30 in the housing 40, and the shape and outer shape
of the support projections 15, 25 can be appropriately selected. Further, the falling
preventive bumps 16, 26 may have any shape and size which can limit the movement of
the coil spring 30 in the compressing direction of the coil spring 30, and the shape
and size thereof can be appropriately selected.
[0040] Moreover, the clearances between the support projections 15, 25 and the falling
preventive bumps 16, 26 of the first plunger 10 and the second plunger 20 may have
any size which can hold the end of the coil spring 30.
[0041] Next, the operation of the probe pin 1 according to the first embodiment will be
described using Figs. 5 to 7B. For convenience of the description, the coil spring
30 and the housing 40 are not shown in Figs. 5 and 6, and the housing 40 is not shown
in Figs. 7A and 7B.
[0042] When the probe pin 1 is to be operated, first, the first plunger 10 and the second
plunger 20 of the probe pin 1 in the original position are pressed from the tip portions
14, 24 to the inside of the coil spring 30. Note that the first and second plungers
10, 20 reciprocate along the axis center C of the coil spring 30 and are brought into
conduction with each other via the slide contact surfaces 17, 27.
[0043] When the first plunger 10 and the second plunger 20 are pressed to the inside of
the coil spring 30, the thin portions 12b, 22b of the elastic sliding pieces 12, 22
are gradually elastically deformed outward (the first plunger 10 is deformed downward
and the second plunger 20 is deformed upward in Fig. 6) because of the curved shapes
of the free ends 12c, 22c.
[0044] When the first plunger 10 and the second plunger 20 are further pressed inward, as
shown in Figs. 5 and 6, the thin portion 22b of the elastic sliding piece 22 of the
second plunger 20 is pressed in a sliding state into a space where the free end 12c
of the elastic sliding piece 12 of the first plunger 10 is pushed out, and the thin
portion 12b of the elastic sliding piece 12 of the first plunger 10 is pressed in
a sliding state into a space where the free end 22c of the elastic sliding piece 22
of the second plunger 20 is pushed out. That is, a state is ensured, in which the
slide contact surface 17 of the first plunger 10 and the slide contact surface 27
of the second plunger 20 are brought into conduction with each other while being in
slide contact with each other.
[0045] At this time, the thin portions 12b, 22b are located in parallel with each other,
and the facing top surfaces 12e, 22e are in press contact with each other. That is,
the first plunger 10 is constantly pressed by spring force of the elastic sliding
piece 22 of the second plunger 20, and the second plunger 20 is constantly pressed
by spring force of the elastic sliding piece 12 of the first plunger 10.
[0046] In the probe pin 1 in the operated position, since the first plunger 10 and the second
plunger 20 press each other by the spring forces of the elastic sliding pieces 12,
22 via the slide contact surfaces 17, 27 of the thin portions 12b, 22b, the first
plunger 10 and the second plunger 20 are constantly in press contact with each other
and are constantly brought into conduction with each other. Accordingly, the first
plunger 10 and the second plunger 20 can be brought into conduction with each other
via the slide contact surfaces 17, 27 of the thin portions 12b, 22b which are a press
contact area, and can obtain stable electric contact.
[0047] Meanwhile, as shown in Figs. 7A and 7B, resultant forces F1, F2 of the spring forces
of the elastic sliding pieces 12, 22 of the first and second plungers 10, 20 act in
the directions of the free ends 12c, 22c of the elastic sliding pieces 12, 22 and
the direction of the axis center C of the first and second plungers 10, 20 (the resultant
force F1 of the spring force of the first plunger 10 acts in an obliquely upper right
direction, and the resultant force F2 of the spring force of the second plunger 20
acts in an obliquely lower left direction). That is, the resultant forces F1, F2 of
the spring forces of the elastic sliding pieces 12, 22 of the first and second plungers
10, 20, which are forces in the oblique directions with respect to the axis center
C of the coil spring 30, are applied to the slide contact surfaces 17, 27 of the first
and second plungers 10, 20. As a result, component forces in the direction of the
axis center C of the pressing forces generated between the slide contact surfaces
17, 27 by the spring forces of the first and second plungers 10, 20 (i.e., component
forces in the direction of the axis center C of the resultant forces F1, F2 of the
spring forces of the elastic sliding pieces 12, 22 of the first and second plungers
10, 20 and component forces in the direction of the axis center C of reaction forces
f1, f2 against the resultant forces F1, F2 of the spring forces of the elastic sliding
pieces 12, 22) act in directions to restore the first and second plungers 10, 20 to
the original positions.
[0048] Therefore, when the probe pin 1 is restored from the operated position to the original
position, the first and second plungers 10, 20 are applied not only with a load based
on the spring force of the coil spring 30, but also a load based on the resultant
forces F1, F2 of the spring forces of the elastic sliding pieces 12, 22 and reaction
forces f1, f2 of the resultant forces F1, F2. It is thereby possible to use the coil
spring 30 with smaller spring force than spring force required for restoring the first
and second plungers 10, 20 to the original positions, and to reduce the size of the
probe pin 1.
[0049] Since the free ends 12c, 22c of the elastic sliding pieces 12, 22 of the first plunger
10 and the second plunger 20 are pushed outward while being pressed each other and
reciprocate in the sliding state, impurities and the like generated on the surfaces
of the slide contact surfaces 17, 27 are rubbed off, and the wiping effect can thus
be obtained.
[0050] Moreover, the first plunger 10 and the second plunger 20 can slide and move until
the free end 12c of the elastic sliding piece 12 of the first plunger 10 (second plunger
20) comes into contact with the thick portion 22a of the elastic sliding piece 22
of the second plunger 20 (first plunger 10) and until the free end 22c of the elastic
sliding piece 22 of the second plunger 20 comes into contact with the thick portion
12a of the elastic sliding piece 12 of the first plunger 10.
[0051] In the probe pin 1 according to the first embodiment, the thicknesses of the body
portion 11 and elastic sliding piece 12 of the first plunger 10 and the thicknesses
of the body portion 21 and elastic sliding piece 22 of the second plunger 20 are made
the same, but this is not restrictive. The thicknesses of the body portion 11 and
elastic sliding piece 12 of the first plunger 10 may be made different from the thicknesses
of the body portion 21 and elastic sliding piece 22 of the second plunger 20.
(Second Embodiment)
[0052] As shown in Figs. 8 to 10B, a probe pin 51 according to a second embodiment of the
present invention includes a first plunger 60, a second plunger 70, and a coil spring
30. The first plunger 60 and the second plunger 70 have electrical conductivity and
are formed by electroforming, for example. Note that identical portions with those
in the first embodiment are denoted with identical reference signs, and the description
thereof will not be given. A difference of the second embodiment from the first embodiment
will be described.
[0053] As shown Figs. 8 and 9, the first plunger 60 is provided with a body portion 11 and
an elastic sliding piece 62 having a Y shape in cross section. Further, the first
plunger 60 has the same width and is formed to be line-symmetrical with respect to
an axis center C of the coil spring 30 shown in Fig. 9. The coil spring 30 is not
shown in Figs. 8 and 9 for convenience of the description.
[0054] The elastic sliding piece 62 is made up of a base portion 63 and an elastic sliding
portion 64 and has the Y shape in cross section. The elastic sliding piece 62 has
an end on the base portion 63 side connected to the other longitudinal end 11b of
the body portion 11, and extends along the axis center C of the coil spring 30. Both
side faces of the base portion 63 are provided with falling preventive bumps 16, 16.
A certain clearance is defined between support projections 15, 15 and the falling
preventive bumps 16, 16 of the body portion 11. Further, the elastic sliding portion
64 is made up of a plate-like portion 64a continued to the base portion 63, and a
pair of elastic pieces 64b, 64b extending from the plate-like portion 64a in the longitudinal
direction. The pair of elastic pieces 64b, 64b have free ends 65, 65 at the tips thereof.
The free ends 65, 65 are curved in a direction away from the axis center C.
[0055] As shown Figs. 8 and 9, the second plunger 70 includes a body portion 21 and a sliding
piece 72. Further, the second plunger 70 has the same width, and is formed to be line-symmetrical
with respect to the axis center C.
[0056] The sliding piece 72 is made up of a base portion 73 and a sliding piece body 74,
has an end on the base portion 73 side connected to the other longitudinal end 21b
of the body portion 21, and extends along the axis center C of the coil spring 30.
Both side faces of the base portion 73 are provided with falling preventive bumps
26, 26. A certain clearance is defined between support projections 25, 25 and the
falling preventive bumps 26, 26 of the body portion 21. The sliding piece body 74
is made up of a plate-like portion 74a having a fixed thickness and continued to the
base portion 73, and a tapered portion 74b extending from the plate-like portion 74a
in the longitudinal direction. The tapered portion 74b has a free end 75 having a
curved shape at the tip thereof, and is formed so as to be gradually tapered toward
the free end 75.
[0057] Note that the free end 75 of the sliding piece 72 of the second plunger 70 is formed
so as to have a thickness which is substantially the same as a size of a clearance
between the free ends 65, 65 of the elastic pieces 64b, 64b of the elastic sliding
portion 64 of the elastic sliding piece 62 of the first plunger 60 in a natural state.
[0058] Further, similarly to the first embodiment, the first plunger 60 and the second plunger
70 of the second embodiment are provided with slide contact surfaces 67, 77 for ensuring
the conduction while coming into slide contact with each other. The slide contact
surface 67 of the first plunger 60 is provided on each of the facing side surfaces
of the pair of elastic pieces 64b, 64b of the elastic sliding portion 64 of the elastic
sliding piece 62. The slide contact surface 77 of the second plunger 70 is provided
on each of the tilted side surface of the tapered portion 74b of the sliding piece
72. The slide contact surfaces 67, 77 are surfaces that come into contact with each
other when the first plunger 60 and the second plunger 70 slide. In the probe pin
51 according to the second embodiment, the first plunger 60 and the second plunger
70 come into contact with each other in two places. For this reason, the first and
second plungers 60, 70 are each provided with two slide contact surfaces 67, 77.
[0059] Surface treatment such as plating or coating can be performed on the slide contact
surfaces 67, 77 or all or part of the first plunger 60 and the second plunger 70 in
accordance with the design.
[0060] The first plunger 10 and the second plunger 20 are slidably combined as follows.
[0061] First, the first plunger 60 and the second plunger 70 are respectively inserted from
both ends of the coil spring 30 toward the inside of the coil spring 30. The first
plunger 60 and the second plunger 70 are disposed such that the free ends 65, 65 of
the elastic sliding piece 62 of the first plunger 60 and the free end 75 of the sliding
piece 72 of the second plunger 70 come face to face.
[0062] When the first plunger 60 and the second plunger 70 are inserted into the coil spring
30, the first end 30a of the coil spring 30 is engaged with and held by the support
projections 15, 15 and the falling preventive bumps 16, 16 of the first plunger 60,
and the second end 30b of the coil spring 30 is engaged with and held by the support
projections 25, 25 and the falling preventive bumps 26, 26 of the second plunger 70.
[0063] As shown in Figs. 11A and 11B, next, the first plunger 60 and the second plunger
70 are further pressed to the inside of the coil spring 30 until the free ends 65,
65 of the elastic sliding piece 62 of the first plunger 60 and the free end 75 of
the sliding piece 72 of the second plunger 70 come into contact with each other (i.e.,
they come into the state shown in Figs. 8 to 10B). Then, the first plunger 60 and
second plunger 70 pressed inside the coil spring 30 are placed into the housing 40.
[0064] At this time, the support projection 15 of the first plunger 60 and the support projection
25 of the second plunger 70 are defined in shape so as to come into contact with the
inner wall of the housing 40 in the state in which the first plunger 60 and the second
plunger 70 are pressed into the coil spring 30. That is, the displacement of the first
and second plungers 60, 70 in the direction orthogonal to the stretching and compressing
directions of the coil spring 30 in the housing 40 can be regulated by the support
projections 15, 25. This enables efficient displacement of the first and second plungers
60, 70 in the direction of the axis center C of the coil spring 30.
[0065] Further, the elastic pieces 64b, 64b of the elastic sliding portion 64 of the elastic
sliding piece 62 of the first plunger 60 come into the state of sandwiching the tapered
portion 74b of the sliding piece body 74 of the sliding piece 72 of the second plunger
70. That is, the slide contact surface 67 of the first plunger 60 and the slide contact
surface 77 of the second plunger 70 are constantly in press contact with each other
and are constantly brought into conduction with each other, and are tilted with respect
to the axis center C of the coil spring 30. Accordingly, the first plunger 60 and
the second plunger 70 can be brought into conduction with each other via the inner
surfaces of the free ends 65, 65 of the elastic sliding piece 62 and the free end
75 of the sliding piece 72 which are the press contact area, and can obtain stable
electric contact.
[0066] Further, the movement of the coil spring 30 in the stretching direction is restricted
by the support projections 15, 25, and the movement of the coil spring 30 in the compressing
direction is restricted by the falling preventive bumps 16, 26. This can prevent wobbling
of the coil spring 30 and can also prevent falling of the coil spring 30, thus preventing
dismantling of the probe pin 51.
[0067] Further, providing the support projections 15, 25 allows efficient transmission of
the spring force of the coil spring 30 to the first and second plungers 60, 70.
[0068] Next, the operation of the probe pin 51 according to the second embodiment will be
described using Figs. 12 to 14B. For convenience of the description, the coil spring
30 and the housing 40 are not shown in Figs. 12 and 13, and the housing 40 is not
shown in Figs. 14A and 14B.
[0069] When the probe pin 51 is to be operated, first, the first plunger 60 and the second
plunger 70 of the probe pin 51 in the original position are pressed from the tip portions
14, 24 to the inside of the coil spring 30. Note that the first and second plungers
60, 70 reciprocate along the axis center C of the coil spring 30 and are brought into
conduction with each other while being in slide contact with each other via the slide
contact surfaces 67, 77.
[0070] When the first plunger 60 and the second plunger 70 are pressed to the inside of
the coil spring 30, the free end 75 of the sliding piece 72 of the second plunger
70 is pressed into the clearance between the elastic pieces 64b, 64b of the elastic
sliding portion 64 of the elastic sliding piece 62 of the first plunger 60 in the
state of sliding on the inner surfaces of the elastic pieces 64b, 64b. Hence the clearance
between the elastic pieces 64b, 64b of the elastic sliding portion 64 of the first
plunger 60 is gradually enlarged by the free end 75 of the sliding piece 72 of the
second plunger 70, and the elastic pieces 64b, 64b of the elastic sliding portion
64 of the first plunger 60 are elastically deformed outward (in a vertical direction
in Fig. 12).
[0071] At this time, since the sliding piece 72 of the second plunger 70 is constantly pressed
by the spring forces of the elastic pieces 64b, 64b of the elastic sliding portion
64 of the elastic sliding piece 62 of the first plunger 60 via the inner surfaces
of the elastic pieces 64b, 64b, the first plunger 60 and the second plunger 70 are
constantly in press contact with each other and are constantly brought into conduction
with each other via the slide contact surfaces 67, 77. Accordingly, the first plunger
60 and the second plunger 70 can be brought into conduction with each other via the
inner surfaces of the elastic pieces 64b, 64b which are the press contact area, and
can obtain stable electric contact.
[0072] Meanwhile, as shown in Figs. 14A and 14B, resultant forces F3, F4 of the spring forces
of the elastic pieces 64b, 64b of the elastic sliding piece 62 of the first plunger
60 act in the direction of the free end 65 of the elastic sliding piece 62 and the
direction of the axis center C (the resultant force F3 of the spring force of the
upper elastic piece 64b acts in an obliquely lower right direction, and the resultant
force F4 of the spring force of the lower elastic piece 64b acts in an obliquely upper
right direction in Figs. 14A and 14B). That is, the resultant forces F3, F4 of the
spring forces of the elastic pieces 64b, 64b of the elastic sliding piece 62, which
are forces in the oblique directions with respect to the axis center C of the coil
spring 30, are applied to the slide contact surfaces 67, 77 of the first plunger 60
and the second plunger 70. As a result, component forces in the direction of the axis
center C of the pressing forces generated between the slide contact surfaces 67, 77
by the spring forces of the first and second plungers 60, 70 (i. e. , component forces
in the direction of the axis center C of the spring forces of the elastic pieces 64b,
64b of the first plunger 60 and component forces in the direction of the axis center
C of reaction forces against the resultant forces F3, F4 of the spring forces of the
elastic pieces 64b, 64b) act in the directions to restore the first and second plungers
60, 70 to the original positions.
[0073] Therefore, when the probe pin 1 is to be restored from the operated position to the
original position, not only a load based on the spring force of the coil spring 30,
but also the component forces in the axis center direction of the spring forces of
the elastic pieces 64b, 64b of the first plunger 60 and the component forces in the
axis center direction of the reflective forces f3, f4 act on the first and second
plungers 60, 70. It is thereby possible to use the coil spring 30 with smaller spring
force than spring force required for restoring the first and second plungers 60, 70
to the original positions, and to reduce the size of the probe pin 51.
[0074] Since the free end 75 of the sliding piece 72 of the second plunger 70 reciprocates
in a sliding state while being pressed by the spring forces of the elastic pieces
64b, 64b of the elastic sliding portion 64 of the first plunger 60, impurities and
the like generated on the surfaces of the slide contact surface 67 of the first plunger
60 and the slide contact surface 77 of the second plunger 70 are rubbed off, and the
wiping effect can thus be obtained.
[0075] Further, slidably movable ranges of the first plunger 60 and second plunger 70 can
be appropriately changed by adjusting the lengths of the elastic pieces 64b, 64b of
the elastic sliding portion 64 of the first plunger 60 and the length of the sliding
piece 72 of the second plunger 70. Note that the slidably movable ranges of the first
plunger 60 and second plunger 70 can also be changed by adjusting a tapered angle
of the tapered portion 74b of the sliding piece body 74 of the sliding piece 72 of
the second plunger 70.
[0076] In the probe pin 51 according to the second embodiment, the free ends 65, 65 of the
elastic sliding piece 62 of the first plunger 60 and the free end 75 of the sliding
piece 72 of the second plunger 70 are curved, but this is not restrictive. For example,
each of these free ends may be formed into a polygonal shape such as a triangular
shape or a square shape.
[0077] In the probe pin 51 according to the second embodiment, the thicknesses of the body
portion 11 and elastic sliding piece 62 of the first plunger 60 and the thicknesses
of the body portion 21 and sliding piece 72 of the second plunger 70 are made the
same, but this is not restrictive. The thicknesses of the body portion 11 and elastic
sliding piece 62 of the first plunger 60 may be made different from the thicknesses
of the body portion 21 and sliding piece 72 of the second plunger 70.
[0078] Further, in the probe pin 51 according to the second embodiment, the clearance between
the free ends 65, 65 of the first plunger 60 in the natural state is formed in size
being the same as the thickness of the free end 75 of the sliding piece 72 of the
second plunger 70, but this is not restrictive. For example, by making the clearance
between the free ends 65, 65 of the first plunger 60 smaller than the thickness of
the free end 75 of the sliding piece 72 of the second plunger 70, the press contact
of the elastic pieces 64b, 64b of the first plunger 60 on the sliding piece 72 of
the second plunger 70 can be enhanced.
[0079] In the probe pins 1, 51 according to the first and second embodiments, the first
plungers 10, 60 and the second plungers 20, 70 are formed by electroforming, but this
is not restrictive. It is possible to arbitrarily select any method so long as it
allows formation of the first plungers 10, 60 and the second plungers 20, 70 according
to the first and second embodiments.
[0080] The coil spring 30 is provided in the probe pins 1, 51 according to the first and
second embodiments, but this is not restrictive. In the first embodiment, the probe
pin 1 may be restored from the operated position to the original position only by
the spring force of the elastic sliding piece 12 of the first plunger 10 and the spring
force of the elastic sliding piece 22 of the second plunger 20. Further, in the second
embodiment, the probe pin 51 can be restored from the operated position to the original
position only by the spring forces of the elastic pieces 64b, 64b of the elastic sliding
portion 64 of the elastic sliding piece 62 of the first plunger 60. Note that in this
case, it is necessary to cover the first plungers 10, 60 and the second plungers 20,
70 with a housing or the like in place of the coil spring 30 so as to prevent dismantling
of the probe pins 1, 51.
[0081] Moreover, in the probe pins 1, 51 according to the first and second embodiments,
the spring length of the coil spring 30 is previously adjusted such that the force
in the compressing direction is applied in the state in which the first plungers 10,
60 and the second plungers 20, 70 are both placed inside the housing 40, but this
is not restrictive. For example, the spring length of the coil spring 30 may be adjusted
by making the first plungers 10, 60 and the second plungers 20, 70 before being placed
into the housing 40 into contact with the housing 40 come into contact with each other
so that they are not applied with force in the state of being placed in the housing
40.
[0082] It is natural that the respective constituents of the probe pins 1, 51 according
to the first and second embodiments may be exchanged or added if possible.
[0083] The probe pins 1, 51 according to the first and second embodiments can be applied
to an electronic device such as an IC test socket.
INDUSTRIAL APPLICABILITY
[0084] The probe pin according to the present invention is not restricted to the first and
second embodiments and is not particularly limited so long as being a probe pin having
a slide contact surface that tilts with respect to an axis center of a coil spring
and can be reduced in size.
REFERENCE SIGNS LIST
[0085]
- 1, 51.
- probe pin
- 10, 60.
- first plunger
- 20, 70.
- second plunger
- 30.
- coil spring
- 40.
- housing
- 11, 21.
- body portion
- 12, 22, 62.
- elastic sliding piece
- 12a, 22a.
- thick portion
- 12b, 22b.
- thin portion
- 12c, 22c.
- free end
- 12d, 22d.
- bottom surface
- 12e, 22e.
- top surface
- 14, 24.
- tip portion
- 15, 25.
- support projection
- 16, 26.
- falling preventive bump
- 17, 27, 67, 77.
- slide contact surface
- 63, 73.
- base portion
- 64.
- elastic sliding portion
- 64a.
- plate-like portion
- 64b.
- elastic piece
- 65, 75.
- free end
- 72.
- sliding piece
- 74.
- sliding piece body
- 74a.
- plate-like portion
- 74b.
- tapered portion